Muscle-invasive bladder cancer (MIBC) is associated with a high risk of developing pelvic recurrence. Although adjuvant external beam radiotherapy (EBRT) decreases the risk of local recurrence, it has been associated with severe toxicity. Previous trials that assessed toxicity applied older techniques of delivering EBRT. It is unclear if modern techniques of EBRT delivery, combining highly conformal EBRT and daily image guidance, could have a better safety profile.